1. Field of the Invention
The present invention relates to a transition metal compound useful as an olefin polymerization catalyst component, an olefin polymerization catalyst, using said transition metal compound and process for producing an olefin polymer using said olefin polymerization catalyst with a high activity.
2. Description of the Related Art
Many processes for producing an olefin polymer with a metallocene complex have been already reported. For example, a process for producing an olefin polymer with a metallocene complex and an aluminoxane is reported in Japanese Patent Publication (Kokai) No. 58-19306. The metallocene complex disclosed therein is a complex having only one transition metal atom in its molecule.
It is disclosed in Japanese Patent Publication (Kokai) No. 4-91095 to use a metallocene complex having a structure in which two transition metal atoms are contained in its molecule and two .eta.'-cyclopentadienyl groups coordinate on each on each of the transition metal atoms, as an olefin polymerization catalyst component.
However, when these metallocene complexes having the structure in which two .eta.'-cyclopentadienyl groups coordinate on one transition metal atom are used as the olefin polymerization catalyst component, there are problems that the molecular weight of an olefin polymer obtained is low and the comonomer reaction rate in copolymerization is low, and the more improvement of activity has been desired from an industrial viewpoint.
Although metallocene complexes in which two transition metal atoms are contained in its molecule and only one .eta..sup.5 -cyclopentadienyl group coordinates on each of transition metal atoms are disclosed in Japanese Patent Publication (Kokai) Nos. 3-163088 and 3-188092, they are complexes having a peculiar structure in which excessive anionic ligands against the valence number of a transition metal atom are combined, and its polymerization activity is not confirmed.
Although a metallocene complex in which two transition metal atoms are contained in its molecule and only one .eta..sup.5 -cyclopentadienyl group coordinates per one transition metal atom is disclosed in Japanese Patent Publication (Kokai) No. 7-126315, it is a complex having a structure in which those two .eta..sup.5 -cyclopentadienyl groups are linked, and there are problems in that the olefin polymerization catalyst using it as a catalyst component has low comonomer reaction rate in copolymerization and the melting point of a copolymer improvement of activity has been desired from an industrial viewpoint.